Hair follicles (HFs) are mini-organs in skin who undergo cyclic growth. Duringthe anagen phase, hair shaft is produced from the bottom part of a HF, referred to as the hair bulb. Proper regulations of the HF bulb cell fate decisions are crucial to maintain an anagen HF, therefore guarantees the continuous production of hair. Recent experiments have provided evidence on how HF bulb is replenished during anagen, and how cells make their fate decisions according to their positions, leading to the HF concentric layered differentiation. In this paper, we develop a hybrid multiscale computational model on HF bulb, integrating cell divisions and movement, diffusive signaling dynamics and intra-cellular gene regulations. Using our model, we first investigate the HF replenishment dynamics driven by different cell dividing strategies, showing that signaling-driven cell division may lead to efficient replenishment dynamics. Next, we use the model to test the primed cell fate decision mechanism, and explore other candidate mechanisms that may contribute to a perfect HF concentric layered differentiation.